To provide a micro high-vacuum pressure sensor, which is housed inside a low-pressure microchip enclosure and which can be manufactured by a well-known microchip manufacturing technique.

The micro pressure sensor uses an electric field generated, by applying a large potential difference across small conductive elements (302, 304) in its inside. Electrons which are discharged by the influence of the electric field and are accelerated to undergo electric field collision with the gas molecules so as to generate positive ions. The positive ions are accelerated towards the conductive element (304) connected to a circuit. A current generated by the ions is measured inside the circuit coupled to the micro pressure sensor, and an internal pressure inside the low-pressure enclosure can be decided. The micro pressure sensor is manufactured by a standard semiconductor manufacturing technique and can be mass-produced economically.